ites associated with human dwelling can be classified as
house dust mites (pyroglyphid mites) and storage mites (non-
pyroglyphid mites). The family Pyroglyphidae contains approximately 18
genera and 46 species of mites (Arlian & Morgan, 2003). House dust mites
inhabit a wide geographical range in the world. Dermatophagoides farinae is
generally the most dominant species in the United States of America, while D.
pteronyssinus is abundant in the United Kingdom (Bonnefoy et al., 2008).
Blomia tropicalis which was formerly categorized as storage dust mite is now
recognized as house dust mites or domestic mites as they are found
extensively in houses (Mariana et al., 2000). B. tropicalis is found in dust from
homes of tropical and subtropical countries, including Spain, India, Taiwan,
Brazil, Colombia, Philippines, Malaysia and Indonesia. House dust mites are
mainly found in areas with skin scales such as carpets, sofas and mattresses.
These three species were isolated from upholsteries of homes in Klang
Valley, Malaysia.
HOUSE DUST MITESHOUSE DUST MITESHOUSE DUST MITESHOUSE DUST MITES
M
MITES
Dermatophagoides farinaeDermatophagoides farinaeDermatophagoides farinaeDermatophagoides farinae
Dermatophagoides pteronysDermatophagoides pteronysDermatophagoides pteronysDermatophagoides pteronyssinsinsinsinusususus
(a) 200x(a) 200x(a) 200x(a) 200x, m, m, m, malealealeale
(b) 200x, female(b) 200x, female(b) 200x, female(b) 200x, female
(a) 200x, male(a) 200x, male(a) 200x, male(a) 200x, male (b) 200x, female(b) 200x, female(b) 200x, female(b) 200x, female
Blomia tropicalisBlomia tropicalisBlomia tropicalisBlomia tropicalis
(a) 200x, male(a) 200x, male(a) 200x, male(a) 200x, male
(b) 200x, female(b) 200x, female(b) 200x, female(b) 200x, female
torage mites are commonly found in storage facilities for grains
such as wheat, corn, oats, barley and hay (Arlian & Morgan,
2003). They may contaminate or invade and thrive in processed foods made
from the grains (e.g. flour, cereals and baking mixes) when these products
become moist or are stored in humid environments. Mites and mite allergens
may be carried over from the raw grains and contaminate the processed
foods, even when they are stored under conditions that prevent mite survival.
Significant exposure to storage mites and their allergens lead to occupational
allergic diseases in agriculture, and baking industry. Aleuroglyphus ovatus
belongs to order of Astigmata and is also known as brown legged grain mite.
A. ovatus has a relatively short life cycle compared with other mites in which
it requires approximately 2-3 weeks only for maturity (Hughes, 1976).
Glycycometus malaysiensis belongs to Aeroglyphidae (super-family
Glycyphagoidea) with very long idiosomal setae (body hairs) (Nadchatram,
2005). Suidasia medanensis belongs to Suidasiidae (super-family Acaroidea)
and are commonly found in houses in tropical and subtropical countries
(Mariana et al., 2000). Both A. ovatus and S. medanensis were isolated from
the dust samples collected from the Animal Holding Facility of the
International Medical University, Malaysia. G. malaysiensis was isolated from
the house dust of homes at Klang Valley, Malaysia.
STORAGE MITESSTORAGE MITESSTORAGE MITESSTORAGE MITES
S
Aleuroglyphus ovatusAleuroglyphus ovatusAleuroglyphus ovatusAleuroglyphus ovatus
(a) 200x, male(a) 200x, male(a) 200x, male(a) 200x, male
(b) 200x, female(b) 200x, female(b) 200x, female(b) 200x, female
GlycycometusGlycycometusGlycycometusGlycycometus (Austroglycyphagus) malaysiensis(Austroglycyphagus) malaysiensis(Austroglycyphagus) malaysiensis(Austroglycyphagus) malaysiensis
(a) 500x, male(a) 500x, male(a) 500x, male(a) 500x, male
(b) 400x, female(b) 400x, female(b) 400x, female(b) 400x, female
SuidaSuidaSuidaSuidasia sia sia sia medanensis / pontificamedanensis / pontificamedanensis / pontificamedanensis / pontifica
(a) 1(a) 1(a) 1(a) 100x, male00x, male00x, male00x, male
(b) 1(b) 1(b) 1(b) 100x, female00x, female00x, female00x, female
MITESMITESMITESMITES ALLERGENSALLERGENSALLERGENSALLERGENS
Mite bodies and mite faeces are the major sources of many allergens in
house dust that induce perennial rhinitis, asthma, atopic dermatitis and other
allergic diseases (Colloff, 2009). Basically, the mite allergens can be
classified into six categories: peptidases (mite allergen groups 1, 3, 6 and 9),
glycosidases (groups 4, 12, 15 and 18), transferases (groups 8 and 20), small
alpha-helical proteins (groups 5, 7 and 21), muscle proteins (groups 10 and
11) and the lipid-binding proteins (groups 2, 13 and 14). The remaining
groups: 16, 17 and 19 are unclassified. Each mite species possesses its own
allergenic components. However, cross-reactivity among the same group of
allergens of different species may often be observed. Hence, the purified and
crude mites can be widely applied for allergenicity studies, establishment of
asthma animal models, diagnostic and/or invention of therapeutic measures.
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